01
Workpiece overcutting
Reason:
1) Elastic knife, the tool strength is not too long or too small, causing the tool to bounce.
2) Improper operation by the operator.
3) Uneven cutting allowance (e.g. leave 0.5 on the curved side and 0.15 on the bottom)
4) Improper cutting parameters (such as large tolerances, fast SF settings, etc.)
improve:
1) The principle of using a knife: it can be big or small, short or long.
2) Add a corner cleaning program, leaving as much margin as possible evenly (the margin on the side and bottom should be consistent).
3) Reasonably adjust cutting parameters and round corners with large margins.
4) By utilizing the SF function of the machine tool, the operator fine tunes the speed to achieve optimal cutting results.

02
Mid point problem
Reason:
1) Inaccurate manual operation by the operator.
2) There are burrs around the mold.
3) The dividing rod has magnetism.
4) The four sides of the mold are not perpendicular.
improve:
1) Manual operation should be carefully checked repeatedly, aiming to be at the same point and height as much as possible.
2) Use an oilstone or file to remove burrs around the mold, then wipe it clean with a cloth, and finally confirm by hand.
3) Before dividing the mold, demagnetize the dividing rod (ceramic dividing rod or other materials can be used).
4) Check if the four sides of the mold are vertical (if there is a large deviation in verticality, review the plan with the fitter).

03
Knife issue
Reason:
1) Inaccurate manual operation by the operator.
2) The tool clamping is incorrect.
3) The blade on the flying knife is incorrect (the flying knife itself has a certain degree of error).
4) There is an error between the R knife, flat bottomed knife, and flying knife.
improve:
1) Manual operation should be carefully checked repeatedly, and the knives should be aligned at the same point as much as possible.
2) When clamping the cutting tool, blow it clean with an air gun or wipe it clean with a cloth.
3) One blade can be used to measure the tool holder and smooth bottom surface of a flying knife.
4) Creating a separate tool alignment program can avoid errors between the flat and flying blades of the R blade.

04
Collision - Programming
Reason:
1) The safety height is insufficient or not set (when the tool or chuck collides with the workpiece during rapid feed G00).
2) The tool on the program sheet and the actual program tool are written incorrectly.
3) The tool length (blade length) on the program sheet and the actual machining depth are written incorrectly.
4) The depth Z-axis reading on the program sheet and the actual Z-axis reading are written incorrectly.
5) Coordinate setting error during programming.
improve:
1) Accurately measuring the height of the workpiece also ensures a safe height above the workpiece.
2) The tools on the program sheet should be consistent with the actual program tools (try to use automatic program sheets or images to generate program sheets).
3) Measure the actual depth of machining on the workpiece, and clearly write the length and blade length of the tool on the program sheet (usually the tool clamping length is 2-3mm higher than the workpiece, and the blade length is 0.5-1.0mm with a clearance).
4) Take the actual Z-axis data on the workpiece and write it clearly on the program sheet. (This operation is usually done manually and needs to be checked repeatedly.).

05
Collision - Operator
Reason:
1) Depth Z-axis tool alignment error.
2) Mid point collision and operation errors (such as unilateral counting without feed radius, etc.).
3) Using the wrong knife (e.g. using a D10 knife for machining with a D4 knife).
4) Program error (e.g. A7. NC went A9. NC).
5) The handwheel shook in the wrong direction during manual operation.
6) Press the wrong direction during manual rapid feed (e.g. - X press+X).
improve:
1) When aligning the depth Z-axis, it is important to pay attention to where the alignment is located. (Bottom, top, analysis surface, etc.).
2) Repeatedly check the middle collision and operation after completion.
3) When clamping the tool, it is necessary to repeatedly check and compare it with the program sheet and program before installing it.
4) The program needs to run one by one in order.
5) When operating manually, the operator should enhance their proficiency in operating the machine tool.
6) When manually moving quickly, you can first raise the Z-axis above the workpiece before moving.

06
Surface accuracy
Reason:
1) The cutting parameters are unreasonable, and the surface of the workpiece is rough.
2) The cutting edge of the knife is not sharp.
3) The tool clamping is too long, and the blade clearance is too long.
4) Scraping, blowing air, and flushing oil are not good.
5) Programming tool cutting method, (can try to consider sequential milling).
6) The workpiece has burrs.
improve:
1) The cutting parameters, tolerances, allowances, speed and feed settings should be reasonable.
2) The tool requires the operator to inspect and replace it irregularly.
3) When clamping cutting tools, the operator is required to clamp them as short as possible, and the blade should avoid being too long.
4) For the downward cutting of flat knives, R-knives, and round nose knives, the speed and feed settings should be reasonable.
5) The workpiece has burrs: it is directly related to our machine tool, cutting tool, and cutting method, so we need to understand the performance of the machine tool and make up for the burrs on the edges.

07
chipped blade
1) Feed too fast
--Slow down to the appropriate feed rate.
2) The feed rate is too fast at the beginning of cutting
--Slow down the feed rate at the beginning of cutting.
3) Clamping looseness (tool)
--Clamp it tightly.
4) Clamping looseness (workpiece)
--Clamp it tightly.
5) Insufficient rigidity (tool)
--Use the shortest allowed knife, clamp the handle deeper, and try milling in a straight direction.
6) The cutting edge of the tool is too sharp
--Change the fragile cutting edge angle in one go.
7) Insufficient rigidity of machine tools and tool holders
--Use machine tools and tool holders with good rigidity.

08
wear
1) The machine speed is too fast
--Slow down and add enough coolant.
2) Hardened material
--Use advanced cutting tools and tool materials to increase surface treatment methods.
3) Chip adhesion
--Change the feed rate, chip size, or clean the chips with cooling oil or air gun.
4) Improper feed rate (too low)
--Increase the feed rate and try sequential milling.
5) Inappropriate cutting angle
--Change to an appropriate cutting angle.
6) The first back angle of the tool is too small
--Change to a larger rear corner.

09
destroy
1) Feed too fast
--Slow down the feed rate.
2) The cutting amount is too large
--Use smaller cutting amounts per blade.
3) The blade length and overall length are too large
--Pinch the handle deeper and use a short knife to try milling smoothly.
4) Excessive wear and tear
--Grind again in the initial stage.

10
chatter mark
1) Feed and cutting speed too fast
--Adjust feed and cutting speed
2) Insufficient rigidity (machine tool and tool holder)
--Use better machine tools and tool holders or change cutting conditions
3) The rear corner is too large
--Change to a smaller back angle and process the blade strip (grind the blade once with an oilstone)
4) Clamping loose
--Clamp the workpiece tightly
5) Consider speed and feed rate
The interrelationship between speed, feed rate, and cutting depth is the most important factor determining the cutting effect. Inappropriate feed rate and speed often lead to reduced production, poor workpiece quality, and significant tool damage.

Use the low-speed range for:
High hardness material
A material with a strong sense of entitlement
Difficult to cut materials
heavy cut
Minimum tool wear
The longest tool life

Use high-speed range for
soft material
Better surface quality
Smaller tool outer diameter
Light cutting
Workpieces with high brittleness
manual operation
Maximum processing efficiency
non-metallic materials

Use high feed rates for
Heavy and coarse cutting
Steel structure
Easy to process materials
Rough machining tools
surfacing
Low tensile strength material
coarse tooth cutter

Use low feed rate for
Light machining, precision cutting
Brittle structure
Difficult to process materials
Small cutting tools
Deep groove processing
High tensile strength material
finishing tool

Reprinted from Mold Manufacturing Mold Information